E-prescribing is rapidly growing across the U.S. but still lags when it comes to controlled substances, Arlington-based Surescripts LLC said in a report on health IT adoption Wednesday.

The developer of the nation's leading network for sharing digital prescriptions and pharmacy records reported 1.04 billion prescriptions were routed electronically in 2013, according to its 2013 National Progress Report and Safe-Rx Rankings.

But about 13 percent of the market — comprising controlled substances such as OxyContin and morphine — has been slow to reach the same levels of growth, said Paul Uhrig, acting chief executive officer, chief administrative officer and chief privacy officer.

He attributes the difference to federal law that — up until four years ago — prohibited e-prescribing of controlled substances due to potential security concerns. The feds relaxed their rules but require certain IT measures taken by electronic medical record companies and pharmacies to protect against security threats and fraud.

“It’s taken some time for all the states to align their laws with the federal law,” Uhrig said.

The company, owned by the National Association of Chain Drug Stores, the National Community Pharmacists Association CVS/Caremark and Express Scripts, processes the vast majority of all electronic prescriptions in the United States. It has more recently built a network to share a wider range of clinical information and notes across the medical world.

E-prescribing is on the rise but still varies by field and geography. For instance, 73 percent of office-based physicians used the tool in 2013, up 4 percentage points from the previous year. Seventy-nine percent of internists were e-prescribing compared with 63 percent of pediatricians. In a ranking of the states' adoption of e-prescribing, D.C. was 50th while Maryland ranked 35th and Virginia ranked 15th.

“What we’ve found in areas with the most success is they had more time,” Uhrig said. “D.C. was also the last jurisdiction to change its law to allow e-prescribing.”